4:15 PM - 4:30 PM
[HTT21-04] Application of portable XRF analysis for provenance of seabed worked stone in coastal are of Kochi Prefecture
Keywords:Principle Component Analysis (PCA), Provenance, pXRF, sedimentary rock, Nankai earthquake
In the XRF spectral data, we clearly recognized peaks for 12 elements (Mg, Si, S, K, Ca, Ti, Mn, Fe, Rb, Sr, Zr, and Pd) in all samples. Therefore, we selected these 12 elements for PCA. In the PCA results for all samples, we could clearly divide those into sandstone group and shale group from the first principle component, where components of Mg, Fe, and Ti strongly influenced. In PCA results for sandstone only, we could see the characteristics of each samples much more clearly. Submerged pillars showed similar characteristics, where a component of Zr was strongly contributed, with Tatsukushi formation in Misaki group (natural exposures and quarries) and foundation stones for main building at Tsumajiro area. Porosity, grain density, and mineral composition were also similar between Tsumajiro pillars, Tatsukushi formation, and a foundation stone.
Our results suggest that the submerged stone pillars were made from Tatsukushi sandstone and had been utilized as building stones for structures such as steps and foundations in Tsumajiro village.